1. Apr 2023

Más contenido relacionado



  2. OUTLINE • Introduction • Indication • Methods of urine collection • Preservation of urine • Examination of urine • Conclusion
  3. INTRODUCTION • A urine analysis/ urinalysis (UA) is one of the most common methods of medical diagnosis . • Urinalysis is a convenient, cost effective and non-invasive means of assessing kidney function and providing an overall assessment of our body’s health. • Is readily available for screening many diseases before symptoms occur.
  4. INTRODUCTION • Routine urinalysis includes assessment of the physical characteristics of urine, chemical analyses and a microscopic examination of urine sediment.
  5. INDICATIONS OF URINALYSIS 1. Information about function of the kidney e.g in suspected renal disease like renal failure, acute glomerulonephritis etc 2. Diagnosis of the urinary tract infection 3. Diagnosis of certain metabolic and systemic disease eg. DM, nephrotic syndrome
  6. INDICATIONS OF URINALYSIS 4. To monitor or assess progress of treatment in conditions such as UTI, kidney stones, and some kidney and liver diseases eg . Nephrotic syndrome, glomerulonephritis, liver cirrhosis 5. As part of routine physical examination
  7. METHODS OF URINE COLLECTION • There are various methods of urine collection depending on the test to be performed. • Urine specimen must be properly collected in- order to obtain reliable information from the result of its analysis. • Use a wide mouthed, clean and dry sterile container.
  8. METHODS OF URINE COLLECTION • MIDSTREAM URINE: pass the first stream of urine to clean the passage. Collect the next stream in a clean and sterile container and pass out the rest. • CATHETER SPECIMEN: mostly used for microbiological examination in critically ill patient or in those with urinary tract obstruction . • SUPRAPUBIC TAP: mostly used in infants.
  9. METHODS OF URINE COLLECTION • FIRST MORNING URINE: Most concentrated specimen, preferred for microscopic examination and for the detection of abnormal amounts of constituents such as proteins or of unusual compounds such as chorionic gonadotropin.
  10. METHODS OF URINE COLLECTION • 24 HOURS SPECIMEN: • On day 1, the bladder must be emptied at the time the collection is to begin and discarded. Thereafter all the urine must be collected into the specimen bottle. • On day 2, the bladder is emptied at the end of the scheduled time into the container. The urine sample should be refrigerated during the collection period.
  11. PRESERVATION OF URINE • Urine sample should be processed within 1 hour of collection if held at room temperature or else refrigerated at 2-8 degree C for not more than 8 hours • Methods of preservation: 1. Keep in refrigerator without any preservative 2. Urine preservatives
  12. URINE PRESERVATIVES • HCL • Acetic acid • Sodium bicarbonate • Boric acid • Toluene • Thymol acid • Formaldehyde
  13. EXAMINATION OF URINE • Physical examination(macroscopic) • Chemical examination(dipstix analysis) • Microscopic examination
  14. PHYSICAL EXAMINATION • Visual appearance • Odour • Turbidity • Volume • Specific gravity • pH
  15. PHYSICAL EXAMINATION • VISUAL APPEARANCE; Colour Normal colour→ pale light yellow to a dark amber colour Orange → Rifampicin, carrot, Vit C Green- UTI, Asparagus Red → haematuria, haemoglobinuria, myoglobinuria, porphyria,nephrolithiasis UTI, rifampicin, Chlopromazine, beets Blue →blue diaper syndrome Purple → Bacteriuria in patient with urinary catheter
  16. • Brown-Gilbert syndrome,tyrosinemia, hepatobiliary disease, fava beans, • Black-Alkaptonuria, malignant melanoma • White-pyuria, chyluria, lipiduria, phosphaturia, hyperoxaluria,
  17. PHYSICAL EXAMINATION • Green or blue → biliverdin, pseudomonal UTI, amitriptyline, methylene blue, iv promethazine • Yellow → concentrated urine, carrots • Brownish-black → bilirubin, melanin, methemoglobin, levodopa, methyldopa
  18. PHYSICAL EXAMINATION • ODOUR 1. Fresh normal urine has an aromatic smell. 2. Fruity or sweet odour: DKA 3. Ammoniacal odour: urea splitting bacterial infection, prolonged bladder retention, 4. Pungent odour: UTI 5. Feacal odour: gastrointestinal-bladder fistulas 6. Sulphuric odour: medication and diet(asparagus) 7. Musty or mousy odour: phenylketonuria 8. Rancid odour: tyrosinaemia
  19. PHYSICAL EXAMINATION • TURBIDITY Normal urine – clear Cloudiness depends on PH and dissolves solids composition. May become turbid when left to stand Generally due to gross bacteriuria. In alkaline urine-amorphous phosphate and carbonate, in acidic urine- amorphous urate
  20. PHYSICAL EXAMINATION • VOLUME •Urine volume ranges btw 400-2000mls/24hrs or 30-50mls / hr or 0.5-1.0 ml/min. >3000ml/24hrs or 50ml/kg is referred to as Polyuria. <400ml/24hrs is Oliguria <100ml/24hrs is Anuria. • Polyuria found in diabetes mellitus , diabetes insipidus ,chronic renal disease, acromegaly and myxedemarenal tubular acidosis , hypercalceamia. • Oliguria or Anuria suggests nephritis, urinary tract obstruction, ARF,ESRD
  21. PHYSICAL EXAMINATION • It is used to assess the state of hydration/dehydration of an individual or as an indicator of the concentrating ability of the kidneys. • SG varies with the solute load to be excreted (consisting primarily of NaCl and urea), as well as with the urine volume • Commonly used device is refractometer and more recently a colorimetric reagent strip method has been added to dipstick.
  22. PHYSICAL EXAMINATION • Normal range for urinary SG is 1.005 to 1.030; dilute specimen1.000- 1.010, concentrated sample 1.025- 1.030. • Decreased USG-diabetes insipidus, pyelonephritis, glomerulonephritis • Increased USG is associated with glycosuria, CHF, dehydration, adrenal insufficiency, liver disease nephrosis,
  23. PHYSICAL EXAMINATION • URINARY pH • It measures the acidity or alkalinity of the urine. Range is 4.5 to 8.0. • Acidic urine is < 4.5 e.g metabolic acidosis, starvation, severe dehydration, chronic diarrhoea • Alkaline urine is > 8.0 e.g bacterial contamination, urinary tract infection, Fanconi’s syndrome
  24. PHYSICAL EXAMINATION • Patients with alkaline urine and UTI is suggestive of a urease splitting organisms with production of ammonia and phosphate crystals, predisposing to calculi formation. • Urinary pH can be measured with dipstick strip, litmus paper and nitrazine paper. • Dipstick strip test contains methyl red and bromthymol blue • Colour range : orange – yellow – green - blue which covers the entire urinary pH range
  25. CHEMICAL EXAMINATION • Protein • Glucose • Ketones • Blood • Bilirubin • Urobilinogen • Nitrite • Leucocytes esterase
  26. CHEMICAL EXAMINATION • PROTEINURIA • Normally, small amount of filtered plasma protein and protein secreted by nephrons (Tamm-horsfall protein) can be found in normal urine. • Proteinuria is defined as urinary protein excretion of > 150mg/day (10 to 20mg/dL).
  27. CHEMICAL EXAMINATION • Causes of proteinuria are as follows; • Functional e.g severe muscular exertion, pregnancy, orthostatic proteinuria • Pre-renal e.g fever, CHF, • Renal e.g acute glomerulonephritis, nephrotic syndrome, renal tumor • Post-renal e.g cystitis, urethritis, prostatitis, bacterial or viral infection.
  28. CHEMICAL EXAMINATION • Dipstick test for proteinuria yields; • Trace = 5 – 20mg/dL • 1+ = 30mg/dL (< 0.5g/day) • 2+ = 100mg/dL (0.5 – 1g/day) • 3+ = 300mg/dL (1 – 2g/day) • 4+ = > 1000mg/dL (> 2g/day) • The reagent on the the dipstick test is tetrabromophenol blue and a citrate pH 3 buffer. • Colour range is from green to blue
  29. CHEMICAL EXAMINATION • Further evaluation of proteinuria usually includes determination of 24-hour urinary protein excretion, microscopic examination of the urinary sediment, urinary protein electrophoresis and assessment of renal function.
  30. CHEMICAL EXAMINATION • GLUCOSE • Ordinarily, urine contains no glucose, but less than 0.1% of normally filtered glucose may appear in the urine (i.e <130mg/24hrs). • Glycosuria can be due to Diabetes Mellitus, Endocrine diseases (eg. Pheachromocytoma, Cushing's syndrome, thyrotoxicosis, hyperpituitarism ) and pancreatic disease .
  31. CHEMICAL EXAMINATION • Glycosuria can also be found in physiological states like pregnancy and lactation. • A +ve test always requires exclusion of diabetes mellitus. • The dipstick reagent strips are specific for glucose. The rely on glucose oxidase to catalyse the formation of hydrogen peroxide, and peroxidase to form chromogen which produce a colour change.
  32. CHEMICAL EXAMINATION • Glucose +02 + H₂O→ glucoronic acid + H202 • H202 + potassium iodide chromogen → oxidised chromogen + H₂O • KETONES • Normal urine contains no ketones • Ketones are produced as a result of incomplete metabolism of fats. • Ketones include 2% acetone, 20% acetoacetic acid and 78% beta-hydroxybutyric acid.
  33. CHEMICAL EXAMINATION • They are usually seen as a result of diabetic ketoacidosis or some form of calorie deprivation (starvation, anorexia, GI disturbances), and vomiting. • The dipstick strip test is based on the reaction of sodium nitroprusside with acetoacetic acid to produce a purple colour.
  34. CHEMICAL EXAMINATION • BLOOD • Hematuria is the presence of an abnormal number of RBC in urine. • Seen in the following conditions: damage/infection/tumors of urinary tract, kidney trauma, renal infarcts, ATN, nephrotoxins, physical stress, and contaminants e.g menstruating women and traumatic bladder catheterization
  35. CHEMICAL EXAMINATION • HEAMOGLOBINURIA is the presence of blood pigments in the urine without the presence of RBCs • Associated with conditions that precipitate hemolytic aneamias e.g. Paroxysmal nocturnal hemoglobinuria, sickle cell disease, malaria, transfusion reaction. • The dipstick strip test is impregnated with buffered tetramethylbenzidine (TMB) and an organic peroxide.
  36. CHEMICAL EXAMINATION • The method depends on detection of the peroxidase activity of hemoglobin, which catalyses the reaction of hydroperoxide and TMB. • The color change ranges from orange through pale to dark green and red cells,free hb and myoglobin are all detected • Microscopic examination of urine can also be used for detection of blood.
  37. CHEMICAL EXAMINATION • BILIRUBIN • It is a highly pigmented compound that is a by-product of hemoglobin degradation. • The detection of urinary bilirubin is an early indication of liver disease (such as hepatitis, hepatic cirrhosis and hepatocellular disease) and its presence or absence can be used to determine the causes of clinical jaundice.
  38. CHEMICAL EXAMINATION • Samples for bilirubin should be protected from light as direct light will cause decomposition. • The dipstick test strip is impregnated with a diazonium salt which react with bilirubin to produce colouration that varies from pink to violet • Results are interpreted as negative, small(+) , moderate(++), and large(+++) amounts of bilirubin.
  39. CHEMICAL EXAMINATION • UROBILINOGEN • A degradation product of bilirubin formed by intestinal bacteria, usually found in urine in small amounts(< 1mg/dL of urine). • Elevated levels may indicate hemolytic anaemia, large hematoma, liver cirrhosis • The dipstick test strip is impregnated with an Ehrlich’s reagent ( p- dimethylaminobenzaldehyde) which react with urobilinogen to produce colours that vary from light to dark pink
  40. CHEMICAL EXAMINATION • NITRITE • This test detect nitrite-reducing bacteria such as the gram negative species that most commonly cause UTI (E.coli, Enterobacter, Klebsiella, Citrobacter and Proteus). • They have enzyme that reduces nitrate present in urine to nitrite. • The dipstick strip test is impregnated with p- arsanilic acid and tetrahydrobenzoquinoline.
  41. CHEMICAL EXAMINATION • The reaction is based on arsanilic acid in the presence of nitrite converting to a diazonium salt, which couples with the N-1- naphthylethylenediamine to produce a pink colour. • It detect populations of bacteria at a value of 10⁵/ml or more, hence spot urine sample may give a false negative result
  42. CHEMICAL EXAMINATION • LEUCOCYTE ESTERASE • The presence of leucocyte esterase is indicative of pyuria (presence of WBCs in the urine). • The dipstick strip test is based on the action of leucocyte esterase in catalysing the hydrolysis of the derivatized pyrrole amino acid ester to liberate 3-hydroxyl-5-phenylpyrrole which reacts with a diazoniumsalt to produce a purple colour
  43. MICROSCOPIC EXAMINATION • Centrifuged, decanted urine aliquot leaves behind a sediment of formed elements that is used for microscopic examination
  44. MICROSCOPIC EXAMINATION • WHITE BLOOD CELLS: 2 – 5 WBCs/hpf is considered normal. A high number of WBCs indicates infection, inflammation or contamination • RED BLOOD CELLS: Erythrocytes greater in number than 0–2/high-power field (HPF) are considered abnormal. Is indicative of trauma, particularly vascular injury, renal/urinary calculi obstruction, pyelonephritis, or cystitis. Hematuria in conjunction with leukocytes is diagnostic of infection
  45. MICROSCOPIC EXAMINATION • EPITHELIAL CELLS: Large, flat, squamous vaginal epithelia are often seen in urine specimens from female patients, and samples heavily contaminated with vaginal discharge may show clumps or sheets of these cells Renal epithelial cells are round, uninucleate cells, and, if present in numbers greater than 2/HPF, indicate clinically significant active tubular injury or degeneration.
  46. • Transitional bladder epithelial cells (urothelial cells) may be flat, cuboidal, or columnar and also can be observed in urine on occasion. Large numbers will be seen only in cases of urinary catheterization, bladder inflammation, or neoplasm
  47. • Miscellaneous Elements Spermatozoa-In males, their presence may indicate prostate abnormalities Yeast cells Parasites-Ova of the trematode Schistosoma hematobium,Enteribius vermicularis, Tricomonas vaginalis
  48. • Bacteria-Normal urine is sterile and contains no bacteria • In fresh specimens, however, large numbers of organisms, or small numbers accompanied by WBCs and the symptoms of urinary tract infection, are highly diagnostic for true infection • Most pathogens seen in urine are gram-negative coliforms (microscopic “rods”) such as Escherichia coli and Proteus sp
  49. • . Asymptomatic bacteriuria common in young girls, pregnant women, and patients with diabetes. • This condition must be taken seriously because, if left untreated, it may result in pyelonephritis and, subsequently, permanent renal damage.
  50. MICROSCOPIC EXAMINATION • CASTS • Casts are precipitated, cylindrical impressions of the nephrons. They comprise Tamm- Horsfall mucoprotein (uromucoid) from the tubular epithelia in the ascending limb of the loop of Henle • Casts in the urinary sediment may be used to localize disease to a specific location in the genitourinary tract.
  51. MICROSCOPIC EXAMINATION • CRYSTALS Acid environment-calcium oxalate, which are normal colorless octahedrons or “envelopes”; they may have an almost starlike appearance. amorphous urates, normal yellowred masses with a grain of sand appearance. Uric acid crystals found in this environment are normal yellow to redbrown crystals that appear in extremely irregular shapes, such as rosettes, prisms, or rhomboids.
  52. • Cholesterol crystals in acid urine are clear, flat, rectangular plates with notched corners. They may be seen in nephrotic syndrome and in conditions producing chyluria and are always considered abnormal • . Cystine crystals are highly pathologic and appear as colorless, refractile, nearly flat hexagons, somewhat similar to uric acid. These are observed in homocystinuria and cystinuria
  53. • Alkaline Environment- • amorphous phosphates, which are normal crystals that appear as fine, colorless masses, resembling sand. • calcium carbonate crystals, which are normal forms that appear as small, colorless dumbbells or spheres. Triple phosphate crystals are colorless prisms of 3–6 sides, resembling “coffin lids.” • Ammonium biurate crystals are normal forms occasionally found in this environment, appearing as spiny, yellow-brown spheres, or “thorn apples.”
  54. Calcium oxalate monohydrate crystals Calcium oxalate di hydrate crystals Cystine crystals
  55. A. Calcuim oxalate crystals. B. Uric acid/urate crystals C. Triphosphate crystals D. Cystine crystals
  56. CONCLUSION • Urinalysis is a very useful screening and diagnostic tool. • If properly done, can yield a great deal of information. • It is important to store strips properly and read at specific time.
  58. REFERENCES • Edmund J. Lamb, Christopher P. Price, kidney function test. In: Tietz textbook of clinical chemistry and molecular diagnostics by Carl A. Burtis, Edward R. Ashwood, David E. Burns. Fifth edition © 2012. Pages 669 – 673. • Jeff A. Simerville, William C. Maxted, John J. Pahira, Urinalysis: A Comprehensive Review. In: Am Fam Physician 2005;71:1153-62. copyright© 2005 American Academy of Family Physicians.